Tens of thousands of climate change activists have been out in force all over the world to raise awareness of the dangers of global warming.Demonstrators armed with alarm clocks converged on the old Paris stock-exchange building to wake public opinion up to the threat of carbon dioxide emissions. As many as 4,000 protests have been taking place in 170 countries around the globe to mark World Climate Day. In Brussels, campaigners staged a symbolic die-in at the Grote Markt, the Belgian capital’s top tourist attraction. The coordinated campaign was designed to highlight ecological concerns in the run-up to the international climate conference to be held in Copenhagen next month. Scientists believe reducing the atmospheric Co2 content from its current 390 parts per million to a sustainable level of 350 would be a suitable target for the world’s politicians to aim for . In Taiwan, the universal “350” message was spelt out for all to see. In Sydney harbour the bells tolled, again symbolically, for those about to die. And off the Great Barrier Reef, divers drew attention to the mortal danger posed by carbon emissions to marine life.